nVidia: Screen tearing when playing videos and resizing windows (Kubuntu 11.04)

[veroslav]

Hi all,

I have installed Kubuntu 11.04 and am experiencing significant screen tearing when playing any videos in VLC player.
Also, the tearing/lag is present each time I try to resize a window. The two issues might be related.

I've searched the forum for similar issues and tried various solutions that were presented there (selecting "Sync to vblank"
in nVidia settings and deselecting the same option in system settings but with no luck).

My computer specifications are quite good (Intel Core i7 860 2,8 GHz, nVidia GeForce GTX 260 1,8 GB, 8 GB DDR3), so
it shouldn't be the cause of the tearing/lag. I am suspecting that using a LCD monitor as output (60 Hz) might require
some system setting changes as well (like forcing the 60 Hz output somewhere), but I am not sure how to change this.

Does anybody knows what might be the cause and how I could solve it? Any tips are more than welcome!

Thank you in advance.

[doctordruidphd]

Re: nVidia: Screen tearing when playing videos and resizing windows (Kubuntu 11.04)

What video driver are you using? nvidia-current, nouveau, or install from the nvidia website?
You can find out what driver you are using by looking at the /var/log/Xorg.0.log file.

If you need to install the NVIDIA driver, one method of doing so is this:
--------------------
Log out of your desktop, at the greeter choose the shutdown button, then choose console login.
Log into the console, and:

sudo service kdm stop
sudo add-apt-repository ppa:ubuntu-x-swat/x-updates
sudo apt-get update
sudo apt-get install nvidia-current
sudo nvidia-xconfig

then reboot.
--------------------

Further information on nvidia drivers:
http://kubuntuforums.net/forums/inde...opic=3117178.0

[oshunluvr]

Re: nVidia: Screen tearing when playing videos and resizing windows (Kubuntu 11.04)

Once you've install the nvidia drivers, post back and I'll point out some tweaks.

[veroslav]

Re: nVidia: Screen tearing when playing videos and resizing windows (Kubuntu 11.04)

Hi,

thank you for your fast replies. I've installed the nVidia propriatery driver a while ago in order to fix a bug that was causing the desktop to crash while resizing Konsole. I remember that I installed the driver through a PPA (might be the same as the one proposed here, can't remeber) and so now the version of the nVidia propriatery driver I am using is 275.09.07.

What should I do next?

Thanks again.

Kind Regards,
Veroslav

[oshunluvr]

Re: nVidia: Screen tearing when playing videos and resizing windows (Kubuntu 11.04)

First of all verify you are not using Compiz.

Install gtkperf and run the full test - this will give you a performance baseline.

Then edit your /etc/X11/xorg.conf file and try these additions in your Device section:

  Option     "Coolbits" "1A"
  Option "TripleBuffer" "True"
#        + Enables triple buffering. "Decreases the time an application stalls while waiting for vblank events, but increases latency slightly" (NVIDIA Readme) 
  Option "UseCompositeWrapper" "True"
#        + Enables the X server's composite wrapper instead of the builtin one. 
  Option "BackingStore" "True"
#        + Cache overlayed areas in case they get redisplayed later 
  Option "OnDemandVBlankInterrupts" "True"
#        + only fire VBlank interrupts in modes where they are needed

Then restart X and run gtkperf again and see if those helped at all.

I would make a backup copy of xorg.conf before editing in case one of the options prevents the restart.

[veroslav]

Re: nVidia: Screen tearing when playing videos and resizing windows (Kubuntu 11.04)

Thank you for your reply, I will try it out. I verified that Compiz is not installed.

I have a question regarding gtkperf before I begin editing xorg.conf: I've looked up this tool in KPackageKit and it appears that it runs its benchmarks on the GTK+ framework. As I understand, KDE uses QT framework, so my question is whether the results that gtkperf displays are relevant in this case? Sorry for being in doubt, I never used this tool before

I would also like to know whether I should select/deselect "Sync to vblank" options in system/nVidia settings respectively before proceeding?

Thanks!

[oshunluvr]

Re: nVidia: Screen tearing when playing videos and resizing windows (Kubuntu 11.04)

gtkperf is just a good and easy to use performance benchmark. People often think that glxgears is for benchmarking, but it isn't at all. It simply checks to see if you have functioning gl.

I do not have Sync to Vblank selected, but you should try it both with and without.

[veroslav]

Re: nVidia: Screen tearing when playing videos and resizing windows (Kubuntu 11.04)

Thank you for your help oshunluvr. I will have a go tonight when I am home from work and report back.

Kind Regards,
Veroslav

[Guest]

Re: nVidia: Screen tearing when playing videos and resizing windows (Kubuntu 11.04)

I had problems with tearing in videos too, especially with full hd videos and dualscreen settings. After messing a while with the settings, I finally got rid of these problems with the following configuration:

kwinrc:

GLVSync=false
UnredirectFullscreen=true

nividia-settings-rc:

SyncToVBlank=1
AllowFlipping=1
XVideoTextureSyncToVBlank=1
XVideoSyncToDisplay=[ The display on which the video should run ]


Did you try exactly this configuration?

Hope this helps...

[veroslav]

Re: nVidia: Screen tearing when playing videos and resizing windows (Kubuntu 11.04)

Thank you so much gramb!

The tearing appears to be much less, if not gone completely

I have not had a chance to play any HD videos, will give that a shot too, but it does look very promissing!

Thanks again!

Kind Regards,
Veroslav